At 2% efficient and 0 cost they would probably be more expensive than current when looking at total installed cost for commercial/residential, maybe even utility.
You can see even at utility scale the panel prices are generally less than 50%.[1] I think 2018 increase was tariff related. Been out of the industry ~5 years so don't follow stuff that closely. Many of the other costs are basically a multiple of # of panels which would be 10x at 2% efficiency.